Crusader Kings II

[Chaotix]

I mean specifically the maximum level. High CA makes a lot of sense because it allows primogeniture and it stops titles from leaving the realm through vassals making dumb marriages with foreigners. All Max CA does is prevent your vassals from declaring war on foreigners, which is something with incredibly limited value considering the massive opinion penalty that it comes with. Vassals are already prevented from fighting eachother within your realm by earlier CA levels. So why would you ever use maximum CA, from a min/maxing perspective? There must be a specific situation.

To be more specific, Max CA prevents vassals from declaring war at all, unless it's to rebel against you.

With Medium/High crown authority, they are prevented from declaring war on other de jure vassals. But if you have territory in say, England and Scotland, and as the King of England your Scottish territory has not de jure drifted yet, then a vassal from England can declare war on a vassal from Scotland, and vice versa, even under Medium CA.

In a huge empire where you are likely to have non-de jure vassals, Max CA will prevent even those pesky inter-de jure wars that you normally can't stop.

That said, I almost never use High or Max CA because I don't want to let my vassals acquire Primogeniture, since it allows them to inherit and build up super-duchies. I usually have High CA for one generation if I want Primo for myself (although half the time I go with Elective instead), and then switch back to Medium in the next generation.